Merge pull request #45 from krawieck/infinite-scroll

.github/workflows/ci.yml

@@ -29,6 +29,9 @@ jobs:
       - name: Run lints
         run: flutter analyze
 
+      - name: Run dartfmt
+        run: dartfmt --dry-run --set-exit-if-changed .
+
       - name: Run tests
         run: flutter test
 

lib/hooks/infinite_scroll.dart

@@ -0,0 +1,6 @@
+import 'package:flutter_hooks/flutter_hooks.dart';
+
+import '../widgets/infinite_scroll.dart';
+
+InfiniteScrollController useInfiniteScrollController() =>
+    useMemoized(() => InfiniteScrollController());

lib/pages/communities_list.dart

@@ -2,7 +2,7 @@ import 'package:cached_network_image/cached_network_image.dart';
 import 'package:flutter/material.dart';
 import 'package:lemmy_api_client/lemmy_api_client.dart';
 
-import '../util/api_extensions.dart';
+import '../util/extensions/api.dart';
 import '../util/goto.dart';
 import '../widgets/markdown_text.dart';
 

lib/pages/community.dart

@@ -11,7 +11,7 @@ import '../hooks/delayed_loading.dart';
 import '../hooks/logged_in_action.dart';
 import '../hooks/memo_future.dart';
 import '../hooks/stores.dart';
-import '../util/api_extensions.dart';
+import '../util/extensions/api.dart';
 import '../util/goto.dart';
 import '../util/intl.dart';
 import '../util/text_color.dart';

lib/pages/full_post.dart

@@ -5,7 +5,7 @@ import 'package:lemmy_api_client/lemmy_api_client.dart';
 
 import '../hooks/memo_future.dart';
 import '../hooks/stores.dart';
-import '../util/api_extensions.dart';
+import '../util/extensions/api.dart';
 import '../widgets/comment_section.dart';
 import '../widgets/post.dart';
 import '../widgets/save_post_button.dart';

lib/pages/instance.dart

@@ -7,7 +7,7 @@ import 'package:intl/intl.dart';
 import 'package:lemmy_api_client/lemmy_api_client.dart';
 import 'package:url_launcher/url_launcher.dart' as ul;
 
-import '../util/api_extensions.dart';
+import '../util/extensions/api.dart';
 import '../util/goto.dart';
 import '../util/text_color.dart';
 import '../widgets/badge.dart';

lib/pages/profile_tab.dart

@@ -4,7 +4,7 @@ import 'package:flutter_hooks/flutter_hooks.dart';
 import 'package:flutter_mobx/flutter_mobx.dart';
 
 import '../hooks/stores.dart';
-import '../util/api_extensions.dart';
+import '../util/extensions/api.dart';
 import '../util/goto.dart';
 import '../widgets/bottom_modal.dart';
 import '../widgets/user_profile.dart';

lib/pages/users_list.dart

@@ -2,7 +2,7 @@ import 'package:cached_network_image/cached_network_image.dart';
 import 'package:flutter/material.dart';
 import 'package:lemmy_api_client/lemmy_api_client.dart';
 
-import '../util/api_extensions.dart';
+import '../util/extensions/api.dart';
 import '../widgets/markdown_text.dart';
 
 class UsersListPage extends StatelessWidget {

lib/widgets/comment.dart

@@ -9,7 +9,7 @@ import 'package:timeago/timeago.dart' as timeago;
 import 'package:url_launcher/url_launcher.dart' as ul;
 
 import '../comment_tree.dart';
-import '../util/api_extensions.dart';
+import '../util/extensions/api.dart';
 import '../util/goto.dart';
 import '../util/text_color.dart';
 import 'bottom_modal.dart';

lib/widgets/infinite_scroll.dart

@@ -0,0 +1,88 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_hooks/flutter_hooks.dart';
+
+import '../hooks/ref.dart';
+
+class InfiniteScrollController {
+  Function() clear;
+
+  InfiniteScrollController() {
+    usedBeforeCreation() => throw Exception(
+        'Tried to use $runtimeType before it being initialized');
+
+    clear = usedBeforeCreation;
+  }
+
+  void dispose() {
+    clear = null;
+  }
+}
+
+class InfiniteScroll<T> extends HookWidget {
+  final int batchSize;
+  final Widget loadingWidget;
+  final Widget Function(T data) builder;
+  final Future<List<T>> Function(int page, int batchSize) fetchMore;
+  final InfiniteScrollController controller;
+
+  InfiniteScroll({
+    this.batchSize = 10,
+    this.loadingWidget =
+        const ListTile(title: Center(child: CircularProgressIndicator())),
+    @required this.builder,
+    @required this.fetchMore,
+    this.controller,
+  })  : assert(builder != null),
+        assert(fetchMore != null),
+        assert(batchSize > 0);
+
+  @override
+  Widget build(BuildContext context) {
+    final data = useState<List<T>>([]);
+    final hasMore = useRef(true);
+    final isFetching = useRef(false);
+
+    useEffect(() {
+      if (controller != null) {
+        controller.clear = () => data.value = [];
+        return controller.dispose;
+      }
+
+      return null;
+    }, []);
+
+    final page = data.value.length ~/ batchSize + 1;
+
+    return ListView.builder(
+      // +1 for the loading widget
+      itemCount: data.value.length + 1,
+      itemBuilder: (_, i) {
+        // reached the bottom, fetch more
+        if (i == data.value.length) {
+          // if there are no more, skip
+          if (!hasMore.current) {
+            return Container();
+          }
+
+          // if it's already fetching more, skip
+          if (!isFetching.current) {
+            isFetching.current = true;
+            fetchMore(page, batchSize).then((newData) {
+              // if got less than the batchSize, mark the list as done
+              if (newData.length < batchSize) {
+                hasMore.current = false;
+              }
+              // append new data
+              data.value = [...data.value, ...newData];
+            }).whenComplete(() => isFetching.current = false);
+          }
+
+          return loadingWidget;
+        }
+
+        // not last element, render list item
+        return builder(data.value[i]);
+      },
+    );
+  }
+}

lib/widgets/post.dart

@@ -13,7 +13,7 @@ import '../hooks/delayed_loading.dart';
 import '../hooks/logged_in_action.dart';
 import '../pages/full_post.dart';
 import '../url_launcher.dart';
-import '../util/api_extensions.dart';
+import '../util/extensions/api.dart';
 import '../util/goto.dart';
 import 'bottom_modal.dart';
 import 'fullscreenable_image.dart';

lib/widgets/save_post_button.dart

@@ -4,7 +4,7 @@ import 'package:lemmy_api_client/lemmy_api_client.dart';
 
 import '../hooks/delayed_loading.dart';
 import '../hooks/logged_in_action.dart';
-import '../util/api_extensions.dart';
+import '../util/extensions/api.dart';
 
 // TODO: sync this button between post and fullpost. the same with voting
 

lib/widgets/user_profile.dart

@@ -5,7 +5,7 @@ import 'package:intl/intl.dart';
 import 'package:lemmy_api_client/lemmy_api_client.dart';
 import 'package:timeago/timeago.dart' as timeago;
 
-import '../util/api_extensions.dart';
+import '../util/extensions/api.dart';
 import '../util/goto.dart';
 import '../util/intl.dart';
 import '../util/text_color.dart';